package czk.concrent.immutableClass.practice;

import java.sql.*;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicIntegerArray;

/**
 * 自定义连接池
 *
 * @Author:ChenZhangKun
 * @Date: 2020/10/29 23:15
 */
public class MockDataSourcePool {
    public static void main(String[] args) {
        // 模拟
        Pool pool = new Pool(5);
        for (int i = 0; i < 10; i++) {
            Thread t = new Thread(() -> {
                Connection connection = pool.borrow();
                try {
                    Thread.sleep(5*1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                pool.back(connection);
            });
            t.start();
        }

    }
}

/**
 * 连接池
 */
class Pool {
    /**
     * 池子大小
     */
    private int poolSize;
    /**
     * 连接状态,与连接数组相对应
     * 0 空闲
     * 1 繁忙
     */
    private AtomicIntegerArray atomicIntegerArray;
    /**
     * 连接
     */
    private Connection[] connections;

    /**
     * 构造方法，初始化
     *
     * @param poolSize 池子大小
     */
    public Pool(int poolSize) {
        this.poolSize = poolSize;
        connections = new Connection[poolSize];
        atomicIntegerArray = new AtomicIntegerArray(poolSize);
        for (int i = 0; i < poolSize; i++) {
            connections[i] = new MockConnection();
        }
    }

    /**
     * 拿连接
     *
     * @return
     */
    public Connection borrow() {
        while (true) {
            // 遍历数组
            for (int i = 0; i < this.poolSize; i++) {
                if (atomicIntegerArray.compareAndSet(i, 0, 1)) {
                    // cas成功，说明此连接还在，返回连接
                    System.out.println(Thread.currentThread().getName() + "拿到连接l");
                    return connections[i];
                }
            }
            // 循环完毕后没有拿到连接，需要阻塞
            synchronized (this) {
                try {
                    System.out.println(Thread.currentThread().getName() + "没有连接了，等待ing");
                    this.wait();
                    System.out.println(Thread.currentThread().getName() + "有链接了，去获取");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    /**
     * 归还连接
     *
     * @param connection
     */
    public void back(Connection connection) {
        for (int i = 0; i < this.poolSize; i++) {
            if (connections[i] == connection) {
                // 返回该链接
                // 只有线程的持有者才能操作此功能，所以没有线程安全问题
                atomicIntegerArray.set(i, 0);
                synchronized (this) {
                    // 唤醒其他线程
                    this.notifyAll();
                    System.out.println(Thread.currentThread().getName() + "归还连接了，你们快去拿");
                }
            }
        }
    }
}

/**
 * 连接
 */
class MockConnection implements Connection {

    @Override
    public Statement createStatement() throws SQLException {
        return null;
    }

    @Override
    public PreparedStatement prepareStatement(String sql) throws SQLException {
        return null;
    }

    @Override
    public CallableStatement prepareCall(String sql) throws SQLException {
        return null;
    }

    @Override
    public String nativeSQL(String sql) throws SQLException {
        return null;
    }

    @Override
    public void setAutoCommit(boolean autoCommit) throws SQLException {

    }

    @Override
    public boolean getAutoCommit() throws SQLException {
        return false;
    }

    @Override
    public void commit() throws SQLException {

    }

    @Override
    public void rollback() throws SQLException {

    }

    @Override
    public void close() throws SQLException {

    }

    @Override
    public boolean isClosed() throws SQLException {
        return false;
    }

    @Override
    public DatabaseMetaData getMetaData() throws SQLException {
        return null;
    }

    @Override
    public void setReadOnly(boolean readOnly) throws SQLException {

    }

    @Override
    public boolean isReadOnly() throws SQLException {
        return false;
    }

    @Override
    public void setCatalog(String catalog) throws SQLException {

    }

    @Override
    public String getCatalog() throws SQLException {
        return null;
    }

    @Override
    public void setTransactionIsolation(int level) throws SQLException {

    }

    @Override
    public int getTransactionIsolation() throws SQLException {
        return 0;
    }

    @Override
    public SQLWarning getWarnings() throws SQLException {
        return null;
    }

    @Override
    public void clearWarnings() throws SQLException {

    }

    @Override
    public Statement createStatement(int resultSetType, int resultSetConcurrency) throws SQLException {
        return null;
    }

    @Override
    public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency) throws SQLException {
        return null;
    }

    @Override
    public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency) throws SQLException {
        return null;
    }

    @Override
    public Map<String, Class<?>> getTypeMap() throws SQLException {
        return null;
    }

    @Override
    public void setTypeMap(Map<String, Class<?>> map) throws SQLException {

    }

    @Override
    public void setHoldability(int holdability) throws SQLException {

    }

    @Override
    public int getHoldability() throws SQLException {
        return 0;
    }

    @Override
    public Savepoint setSavepoint() throws SQLException {
        return null;
    }

    @Override
    public Savepoint setSavepoint(String name) throws SQLException {
        return null;
    }

    @Override
    public void rollback(Savepoint savepoint) throws SQLException {

    }

    @Override
    public void releaseSavepoint(Savepoint savepoint) throws SQLException {

    }

    @Override
    public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {
        return null;
    }

    @Override
    public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {
        return null;
    }

    @Override
    public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {
        return null;
    }

    @Override
    public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws SQLException {
        return null;
    }

    @Override
    public PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws SQLException {
        return null;
    }

    @Override
    public PreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException {
        return null;
    }

    @Override
    public Clob createClob() throws SQLException {
        return null;
    }

    @Override
    public Blob createBlob() throws SQLException {
        return null;
    }

    @Override
    public NClob createNClob() throws SQLException {
        return null;
    }

    @Override
    public SQLXML createSQLXML() throws SQLException {
        return null;
    }

    @Override
    public boolean isValid(int timeout) throws SQLException {
        return false;
    }

    @Override
    public void setClientInfo(String name, String value) throws SQLClientInfoException {

    }

    @Override
    public void setClientInfo(Properties properties) throws SQLClientInfoException {

    }

    @Override
    public String getClientInfo(String name) throws SQLException {
        return null;
    }

    @Override
    public Properties getClientInfo() throws SQLException {
        return null;
    }

    @Override
    public Array createArrayOf(String typeName, Object[] elements) throws SQLException {
        return null;
    }

    @Override
    public Struct createStruct(String typeName, Object[] attributes) throws SQLException {
        return null;
    }

    @Override
    public void setSchema(String schema) throws SQLException {

    }

    @Override
    public String getSchema() throws SQLException {
        return null;
    }

    @Override
    public void abort(Executor executor) throws SQLException {

    }

    @Override
    public void setNetworkTimeout(Executor executor, int milliseconds) throws SQLException {

    }

    @Override
    public int getNetworkTimeout() throws SQLException {
        return 0;
    }

    @Override
    public <T> T unwrap(Class<T> iface) throws SQLException {
        return null;
    }

    @Override
    public boolean isWrapperFor(Class<?> iface) throws SQLException {
        return false;
    }
}
